AutoUnpackWars is a feature of Tomcat which automatically unpacks WAR files before deployment, creating all the files and folders that are stored in the WAR file.

This is useful for a number of reasons:

An unpacked application is less likely to be locked by Tomcat, allowing it to be undeployed more easily.

Unpacked applications are able to write to their Application Root and other folders such as WEB-INF, because the folders exist in the file system. When the application is deployed as a WAR file, these folders don't exist.

Class and jar files exist in the file system, which is accessed faster than a WAR file.